1. Field of the Invention
This invention relates to a structure which is formed from a multiplicity of links that are joined end to end in a ball and socket joint at the juncture of each pair of links. More particularly, this invention relates to a structure of complex design and construction, for example, an arm for transferring metal workpieces in an automotive parts stamping operation, which can be rapidly and precisely constructed from a multiplicity of links of standard sizes that are joined to one another end to end.
2. Description of the Prior Art
U.S. Pat. No. 4,648,733 (R. Merkt) discloses a conduit system which is made up of plastic tubular links that are joined end to end in articulating, ball and socket connections. However, there is no teaching in this reference that its disclosure is applicable to the construction of a device which must support a sizeable load cantilevered at the end thereof, for example, a stamping press work transfer arm, and the use of the preferred material of construction of this reference, polyamide, would be unsatisfactory for such a load bearing device because of the limited strength, low modulus of elasticity, and low resistance to elevated temperatures of such material. Thus, such work transfer arms are now usually custom designed and fabricated from ferrous metals, and as such these work transfer arms are heavy, expensive, and adjustable after construction and assembly, if at all, only with great difficulty. U.S. Pat. No. 4,471,595 (S. Lanzafame) also discloses a structure which is made up of a multitude of links that are pivotally connected to one another in an end to end manner. However, each link of the structure of this reference is complex in construction, being made up of a pair of separate clamping members with recesses therein for engaging clamping units, and with a threaded fastener for increasing the load of the clamping members on the clamping unit.